<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title></title>
    <style>
        div {
            width: 100px;
            height: 100px;
            background: red;
            background: blue !important;
        }
    </style>
</head>
<body>
<!--
    !important		提升样式优先级
        比行间样式的优先级还要高
-->
<div style="background: green;"></div>
</body>
</html>
